Over the last few years, automatic coffee makers have gained wide popularity. In these devices a measured amount of water is poured into the back container of the coffee maker. The ground coffee is placed in a paper filter in a plastic holder which fits on top of a glass decanter which is placed under the pour spout of the coffee maker. The water is heated and fed out of the pour spout through the ground coffee and filter into the decanter. A heating element is located in the base of the coffee maker and after the coffee has been brewed, it is presumably designed to maintain the temperature of the coffee.
However, in order to maintain a reasonable temperature for a full pot of coffee, the warmers have been designed such that they over heat smalleer quantities of coffee and in particular are completely insufficient to maintain a reasonable temperature for a few leftover cups of coffee.
For example, in a typical coffee maker, the coffee reaches the decanter immediately after the brewing step at about 190.degree. F. When ten cups, as measured on the device, are brewed the coffee held in the decanter has cooled to about 158.degree. F. after one hour with the warmer on. When eight cups are brewed the coffee is maintained at 160.degree. F. after one hour but a full one-half cup liquid measure has evaporated. If six cups have been brewed the temperature after one hour has reached 164.degree. F. If three cups are brewed the temperature has reached 170.degree. F. after one hour and even more than the one-half cup liquid measure has been lost to evaporation. It will be apparent that the quality of the coffee suffers as a result of the evaporation and the variable temperature and storage on the heater of lesser quantities of coffee is not only impractical but dangerous. The smaller amount of coffee in the decanter the higher the temperature reaches until a hazard results.
While this is one example of difficulties with warmers, it will be apparent to the reader that these difficulaties and problems with coffee makers are not uncommon with any warmer or heating element device where the temperature of the liquid is preferably maintained at a given level irrespective of the amount of liquid in the container. For all simple warmers or heaters used for food, heat conduction and cooling effects will depend upon the amount of liquid in the container thus causing the temperature of the liquid to vary depending upon that amount. For many applications other than coffee this is totally unsatisfactory and warmers for tea, sauces, and the like are particularly susceptible to this problem. It will be apparent that there are other applications outside the food field where this problem exists and it is particularly troublesome when it is not practical nor desirable to insert some type of electrical control sensor in the liquid itself.
Accordingly, it is an object of this invention to provide a holder and height adjuster which will be directly responsive to the amount of liquid held in the container to be warmed. It is an additional object of this invention to provide an adjuster which may be attached to the warmer without interconnection into the electrical circuit of the warmer.
It is an additional object of this invention to provide an adjuster directly responsive to the amount of liquid to be warmed such that a single chosen temperature may be maintained irrespective of the amount of liquid removed from the container.
It is an additional object of this invention to provide a holder and height adjuster capable of maintaining a chosen temperature while avioiding any direct contact with the liquid being warmed.
It is an additional object of this invention to provide a holder and height controller which is directly responsive to the amount of liquid being warmed and is adjustable to a prechosen temperature to be held irrespective of the amount of liquid being warmed.
It is an object of this invention to provide a holder and height adjuster capable of maintaining a single prechosen temperature in a container wherein the heat transfer characteristics are such that the temperature maintained is dependant upon the amount of liquid in the container.